Small-aperture intermittent deep hole machining process

Abstract

According to the small-aperture intermittent deep hole machining technology, machining is conducted through a small-aperture intermittent deep hole machining tool set, and the small-aperture intermittent deep hole machining tool set comprises a first tool, a second tool, a third tool, a fourth tool and a fifth tool. When the first multi-blade supporting shaft and the second multi-blade supporting shaft are used for machining, the multi-blade supporting structure plays a supporting and guiding role in a front section hole, the overall machining rigidity and stability are enhanced, cutter breakage is avoided, the whole cutter composition cost is low, and machining of small-aperture intermittent deep holes can be efficiently and reliably completed.

Description

Technical Field

[0001] The invention belongs to the technical field of tool processing, and in particular relates to a small-diameter intermittent deep hole processing technology. Background Art

[0002] With the increase in the types of gearboxes, the related lubricating oil circuits on the housing parts are becoming more and more complicated. There are more and more small-diameter intermittent oil channel deep holes with a diameter of less than D7 and a hole depth of more than 50 times the diameter on the housing of agricultural AT hydraulic gearboxes such as cotton pickers. The oil channel intersects with the bearing hole eccentrically, and the intermittent hole mouth surface has a large slope, which makes the processing extremely difficult. Because the tool overhang is too long and the rigidity is weak, the ordinary deep hole drill has serious vibration and is very easy to break, resulting in low processing efficiency and high tool cost.

[0003] In particular, the outer dimensions of agricultural gearbox housings are relatively large, so there are many deep cavities and deep hole structures on the housing. Generally, the deep hole processing of oil channels adopts the scheme of guide tool + gun drill or guide tool + integral alloy deep hole drill, but when these two schemes process small-diameter intermittent deep holes, the tool breakage rate is extremely high in the processing of the rear section of the hole.

[0004] like Figure 1 As shown in the figure, it is a small-diameter oil hole on our company's AT gearbox, which intersects eccentrically with the bearing hole, and divides the oil hole into two discontinuous structures: the front section hole and the rear section hole. The hole diameter is 6≤D≤7mm, and the hole diameter tolerance requirement is relatively loose, with an upper difference of b=0.12mm; the hole depth L is generally above 350mm, the aspect ratio L / D≥50, the axial length of the rear section hole mouth bevel L4>1.2*D, and the slope is greater than 50°. When ordinary alloy deep hole drills or gun drills are used to process the rear section hole mouth bevel, the drill bit is only subjected to radial force on one side, and cannot be centered, the cutting stability is poor, and the cutter head vibrates. Because the rear end of the tool lacks support in the front hole, the drill bit is easily deflected and broken, and the processing of the rear section hole is extremely difficult. When the hole depth L exceeds the standard alloy bar length of 330mm, the overall alloy deep hole drill needs to be customized with non-standard bar material, and the tool cost is extremely high. Because the tool overhang depth is too long, the processing rigidity is poor, and the cutting parameters need to be reduced, which limits the processing efficiency. How to effectively reduce the problems of tool chattering and tool breakage in the later stage of hole processing, and to efficiently and reliably complete the processing of small-diameter intermittent deep holes at a lower tool cost, is a key issue that needs to be solved urgently. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a small-diameter intermittent deep hole processing technology to solve the problems of tool vibration and tool breakage in the latter stage of hole processing of existing tools.

[0006] To achieve the above object, the technical solution adopted by the present invention includes:

[0007] A small-diameter intermittent deep hole processing technology, which is processed by a small-diameter intermittent deep hole processing tool set, wherein the small-diameter intermittent deep hole processing tool set includes a first tool, a second tool, a third tool, a fourth tool and a fifth tool;

[0008] The first tool is a first pilot drill, comprising a first tool head;

[0009] The second tool comprises a second cutter head, a groove length l21 of the second cutter head> a front hole length L1, a diameter d2 of the second cutter head< a diameter d1 of the first cutter head, and a drill point angle α2 of the second cutter head< a drill point angle α1 of the first cutter head;

[0010] The third tool includes a third cutting head and a first support shaft coaxially connected from front to back, the third cutting head and the first multi-blade support shaft have equal diameters, and satisfy l31>L3 and (L1+L3+L4)-(l31+l32)≤(25%~30%)*L1; wherein l31 is the length of the third cutting head, L3 is the distance between the adjacent ends of the front hole and the rear hole, L4 is the hole length of the chamfered surface of the rear hole, and l32 represents the length of the first multi-blade support shaft;

[0011] The fourth tool is a second guide drill, including a fourth cutter head, a cutter bar and a second multi-blade support shaft coaxially connected from front to back, the fourth cutter head, the cutter bar and the second multi-blade support shaft have equal diameters, satisfying l41>L3 and (L1+L3+L4+1.5D)-(l41+l42)≤(25%~30%)*L1; wherein l41 represents the length after the fourth cutter head and the cutter bar are connected, and l42 represents the length of the second multi-blade support shaft;

[0012] The fifth tool comprises a fifth cutter head, and the fifth cutter head is provided with a chip removal groove from the front end to the rear, and the chip removal groove length l51>L1+L3+L2;

[0013] The specific steps of the processing technology are as follows:

[0014] S1, use the first tool 1 to drill the guide hole of the front hole and chamfer and deburr the hole mouth, the drilling depth is (1.5-2)*D;

[0015] S2, using the second tool 2 to drill through the front hole to a depth of L1+(4-6) mm;

[0016] S3, using the third tool 3 to countersink the inclined surface of the rear hole into a flat surface, with a processing depth of L1+L3+L4;

[0017] S4, using the fourth tool 4 to drill the guide hole of the rear section hole, the processing depth is L1+L3+L4+1.5D;

[0018] S5, using the fifth tool 5 to drill the rear hole to the depth required by the drawing, the processing depth is L1+L3+L2.

[0019] Preferably, the first cutter head diameter d1 is The drill point angle α1 of the first tool head is 140°, and the drill depth l11 is 1.5D to 2D; wherein D is the diameter of the hole to be processed.

[0020] Preferably, the edge band of the second cutting head includes a double edge band and a single edge band coaxially connected from front to back, and the length l22 of the double edge band is 6D to 7D.

[0021] Preferably, the drill diameter d2 of the second tool is The drill point angle α2 of the second tool is 136°.

[0022] Preferably, the third cutter head is a 2-tooth flat-bottom cutter head, the cutting edge length l33 of the third cutter head is ≥ 2.5*L4, and the diameter d3 of the third cutter head is d2-d3=0.005~0.025; the rake angle α3 of the first multi-blade support shaft is 90°, the blade width β3 is 1.5, and the helix angle α31 is 20~25°.

[0023] Preferably, the diameter of the blade body of the third blade head is shrunk by 0.05 to 0.1 mm on one side.

[0024] Preferably, the first multi-blade support shaft is a 6-blade support shaft.

[0025] Preferably, the drill point angle α4 of the fourth cutter head is 140°, the blade length l43 of the fourth cutter head is 4D, the drilling depth is 1.5D to 2D, and the diameter d4 of the fourth cutter head is

[0026] Preferably, the diameter of the knife rod is shrunk by 0.05 to 0.1 mm on one side.

[0027] Preferably, the fifth cutter head diameter d5 is The drill point angle α5 of the fifth cutter head is 120°.

[0028] Compared with the prior art, the advantages of the present invention are:

[0029] (1) The present invention provides a small-diameter intermittent deep hole processing technology, in which the front section hole is used as a guide hole. The multi-blade support structure plays a supporting and guiding role in the front section hole during processing through the first multi-blade support shaft and the second multi-blade support shaft, thereby enhancing the overall processing rigidity and stability and avoiding tool breakage. The entire tool group has a low cost and can efficiently and reliably complete the processing of small-diameter intermittent deep holes.

[0030] (2) The present invention provides a small-diameter intermittent deep hole processing process, wherein the first tool and the second tool are both front-stage hole processing tools, the first tool is a front-stage hole processing guide drill, and the second tool is a front-stage hole processing deep hole drill. Processing the front-stage hole alone can shorten the tool overhang and maximize the tool rigidity. An integral cemented carbide with an internal coolant hole can be used, so that higher cutting parameters can be used to improve processing efficiency, while ensuring the front-stage hole processing accuracy and hole wall smoothness, laying a good foundation for the back-stage hole processing.

[0031] (3) A small-diameter intermittent deep hole processing process of the present invention, the third tool, the fourth tool and the fifth tool are the rear-stage hole processing tools, the third tool is used for countersinking the inclined surface of the hole mouth in the rear stage of hole processing, when countersinking the inclined surface of the hole mouth in the rear stage, the first support shaft plays a supporting and guiding role in the front stage hole, the first support shaft is simple and easy to manufacture in the tool and the precision is well guaranteed, the third tool is used to countersink the inclined surface of the hole mouth in the rear stage hole into a plane, so that the subsequent fourth tool drill tip can be well centered when drilling, avoiding tool breakage; the fourth tool is the guide drill for the rear-stage hole processing, and the design of the second multi-blade support shaft ensures effective support at all times during processing; the guide hole of the rear-stage hole is drilled by the tool, which plays a guiding role for the tool drill tip, ensuring that the tool 5 drills stably, completing the entire deep hole processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 This is a schematic diagram of the small diameter oil hole on the AT gearbox;

[0034] Figure 2 It is a structural schematic diagram of a small-diameter intermittent deep-hole machining tool set of the present invention;

[0035] The numbers in the figure are:

[0036] 1 first tool, 1-1 first tool head;

[0037] 2 second tool, 2-1 second cutter head, 2-12 double edge band, 2-11 single edge band;

[0038] 3 third tool, 3-1 third tool head, 3-2 first multi-blade support shaft, 3-10 tool body;

[0039] 4 fourth tool, 4-1 fourth tool head, 4-2 tool rod, 4-21 second multi-blade support shaft;

[0040] 5 fifth tool, 5-1 fifth cutter head, 5-10 chip groove. DETAILED DESCRIPTION

[0041] The invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the invention.

[0042] It should be noted that the directional terms mentioned in this article are consistent with the specific directions on the paper in the drawings of the specification or the corresponding directions in the space shown in the drawings; all components and equipment in the present invention, unless otherwise specified, are all components and equipment known in the prior art.

[0043] The aperture to be processed disclosed in this embodiment is D, 6≤D≤7mm, and the aperture tolerance requirement is b=0.12. The depth of the hole to be processed L is greater than 350mm, and the aspect ratio L / D≥50; the axial length of the inclined surface of the rear hole mouth L4>1.2*D, and the inclination is greater than 50°.

[0044] Example

[0045] This embodiment discloses a small-diameter intermittent deep hole machining process, which is machined by a small-diameter intermittent deep hole machining tool set, and the small-diameter intermittent deep hole machining tool set includes a first tool 1, a second tool 2, a third tool 3, a fourth tool 4 and a fifth tool 5;

[0046] The first tool 1 is a first pilot drill, comprising a first tool head 1 - 1 ;

[0047] The second tool 2 includes a second cutter head 2-1, a groove length l21 of the second cutter head 2-1> a ​​front hole length L1, a diameter d2 of the second cutter head 2-1< a diameter d1 of the first cutter head 1-1, and a drill point angle α2 of the second cutter head 2-1< a drill point angle α1 of the first cutter head 1-1;

[0048] The third tool 3 includes a third cutter head 3-1 and a first support shaft 3-2 which are coaxially connected from front to back, and the third cutter head 3-1 and the first multi-blade support shaft 3-2 have equal diameters, satisfying l31>L3 and (L1+L3+L4)-(l31+l32)≤(25%~30%)*L1; wherein l31 is the length of the third cutter head 3-1, L3 is the distance between the adjacent ends of the front section hole and the rear section hole, L4 is the hole length of the inclined surface of the hole mouth of the rear section hole, and l32 represents the length of the first multi-blade support shaft 3-2;

[0049] The fourth tool 4 is a second guide drill, including a fourth tool head 4-1, a tool rod 4-2 and a second multi-blade support shaft 4-21 coaxially connected from front to back, and the fourth tool head 4-1, the tool rod 4-2 and the second multi-blade support shaft 4-21 have equal diameters, satisfying l41>L3 and (L1+L3+L4+1.5D)-(l41+l42)≤(25%~30%)*L1; wherein l41 represents the length after the fourth tool head 4-1 and the tool rod 4-2 are connected, and l42 represents the length of the second multi-blade support shaft 4-21;

[0050] The fifth tool 5 comprises a fifth tool head 5-1, and the fifth tool head 5-1 is provided with a chip removal groove 5-10 from the front end thereof to the rear, and the length of the chip removal groove 5-10 is l51>L1+L3+L2;

[0051] Its function is as follows: the first tool 1 and the second tool 2 are both front-stage hole processing tools, the first tool 1 is the front-stage hole processing guide drill, and the second tool 2 is the front-stage hole processing deep hole drill. Processing the front-stage hole alone can shorten the tool overhang and maximize the tool rigidity. Solid carbide with internal cooling holes can be used, which can not only use higher cutting parameters to improve processing efficiency, but also ensure the front-stage hole processing accuracy and hole wall smoothness, laying a good foundation for the back-stage hole processing. The third tool 3, the fourth tool 4 and the fifth tool 5 are the tools for processing the rear hole. The third tool 3 is used for countersinking the inclined surface of the hole mouth in the rear hole processing. When countersinking the inclined surface of the hole mouth in the rear hole, the first support shaft 3-2 plays a supporting and guiding role in the front hole. The first support shaft 3-2 is simple and easy to manufacture and has good precision. The third tool 3 is used to countersink the inclined surface of the hole mouth in the rear hole into a plane, which can make the subsequent fourth tool 4 drill well centered when drilling, avoiding tool breakage; the fourth tool 4 is a guide drill for processing the rear hole, and the design of the second multi-blade support shaft 4-21 ensures effective support during processing. Use tool 4 to drill the guide hole of the rear hole, which plays a guiding role for the drill tip of tool 5, ensuring that tool 5 drills stably and completes the entire deep hole processing.

[0052] The difficulty in processing the small-diameter intermittent deep holes disclosed in this scheme lies mainly in the processing of the rear-section holes. In order to solve the problem of tool breakage, the front-section holes are used as guide holes. The multi-blade support structure plays a supporting and guiding role in the front-section holes through the first multi-blade support shaft 3-2 and the second multi-blade support shaft 4-21 during processing, thereby enhancing the overall processing rigidity and stability, and effectively solving the problems of tool breakage, high tool cost and low processing efficiency.

[0053] The first tool disclosed in this embodiment is made of cemented carbide, and the diameter d1 of the first tool head 1-1 is The drill point angle α1 of the first cutter head 1 - 1 is 140°, and the drill depth l11 is 1.5D to 2D; the compound hole chamfer improves efficiency, increases the shank diameter, and improves rigidity.

[0054] The second tool disclosed in this embodiment is made of cemented carbide. The edge band of the second tool head 2-1 includes a double edge band 2-12 and a single edge band 2-11 coaxially connected from front to back. The length l22 of the double edge band 2-12 is 6D to 7D. The drill diameter d2 of the second tool 2 is The drill point angle α2 of the second tool 2 is 136°.

[0055] The third tool disclosed in this embodiment is made of powder metallurgy high-speed steel, which has better toughness than carbide tools, is not easy to break, and has lower cost than alloy tools. The third tool head 3-1 is a 2-tooth flat-bottom tool head. The flat-bottom tool head is only subjected to axial force during processing, avoiding the problem of uneven radial force on the inclined surface and being unable to center the drill bit; the design of 2 teeth can ensure sufficient chip space. The cutting edge length l33 of the third tool head 3-1 is ≥2.5*L4, and the diameter d3 of the third tool head 3-1 is d2-d3=0.005-0.025; the rake angle α3 of the first multi-blade support shaft 3-2 is 90°, the blade width β3 is 1.5, and the helix angle α31 is 20-25°. The diameter of the cutter body 3-10 of the third cutter head 3-1 disclosed in this embodiment is necked down by 0.05-0.1mm on one side to avoid stucking when entering the hole; the first multi-blade support shaft 3-2 is a 6-blade support shaft.

[0056] The drill point angle α4 of the fourth cutter head 4-1 disclosed in this embodiment is 140°, the blade length l43 of the fourth cutter head 4-1 is 4D, the drilling depth is 1.5D to 2D, and the diameter d4 of the fourth cutter head 4-1 is The diameter of the tool rod 4-2 is shrunk by 0.05 to 0.1 on one side to avoid jamming when entering the hole. The fourth tool head 4-1 is made of carbide tool rod 4-2, which is made of powder metallurgy high-speed steel. The two are sleeved and welded to increase the contact area and welding strength. At the same time, the butt welding structure greatly reduces the tool cost compared to the integral carbide drill bit. At the same time, the carbide tool head also ensures sufficient tool life and processing efficiency. At the same time, the front angle, blade width, and helix angle of the second multi-blade support shaft 4-21 disclosed in this embodiment are the same as those of the first multi-blade support shaft 3-2.

[0057] The diameter d5 of the fifth cutter head 5-1 disclosed in this embodiment is The drill point angle α5 of the fifth cutter head 5-1 is 120°. A brazed carbide head gun drill is used. Compared with a solid carbide drill, the brazed carbide gun drill has low tool cost, good toughness, and is not easy to break. The tool has internal cooling to effectively remove chips, and the carbide cutter head has a guide strip structure, which can always drill stably after entering the guide hole.

[0058] The specific steps of the machining process of small-diameter intermittent deep holes using a tool set in this embodiment are as follows:

[0059] S1, use the first tool 1 to drill the guide hole of the front hole and chamfer the hole to remove burrs, and the drilling depth is (1.5~2)*D;

[0060] S2, use the second tool 2 to drill through the front hole to a depth of L1+(4-6) mm;

[0061] S3, using the third tool 3 to countersink the inclined surface of the rear hole into a flat surface, with a processing depth of L1+L3+L4;

[0062] S4, use the fourth tool 4 to drill the guide hole of the rear section hole, and the processing depth is L1+L3+L4+1.5D;

[0063] S5, use the fifth tool 5 to drill the rear hole to the depth required by the drawing, the processing depth is L1+L3+L2, and the process is completed Figure 1 The shown figure shows the processing of small diameter intermittent deep holes.

[0064] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0065] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations. In addition, the various different embodiments disclosed in this solution can also be combined arbitrarily, as long as they do not violate the ideas of this disclosure, they should also be regarded as the contents invented by this disclosure.

Claims

1. A small-diameter intermittent deep hole processing process, characterized in that: The small-diameter intermittent deep hole machining tool set is processed, and the small-diameter intermittent deep hole machining tool set comprises a first tool (1), a second tool (2), a third tool (3), a fourth tool (4) and a fifth tool (5); The first tool (1) is a first guide drill, comprising a first tool head (1-1); the second tool (2); The second tool (2) comprises a second cutter head (2-1), a groove length l21 of the second cutter head (2-1)> a front hole length L1, a diameter d2 of the second cutter head (2-1)< a diameter d1 of the first cutter head (1-1), and a drill point angle α2 of the second cutter head (2-1)< a drill point angle α1 of the first cutter head (1-1); The third tool (3) comprises a third tool head (3-1) and a first support shaft (3-2) which are coaxially connected from front to back, the third tool head (3-1) and the first multi-blade support shaft (3-2) are of equal diameter, satisfying l31>L3 and (L1+L3+L4)-(l31+l32)≤(25%-30%)*L1; wherein l31 is the length of the third tool head (3-1), L3 is the distance between the adjacent ends of the front hole and the rear hole, L4 is the hole length of the inclined surface of the rear hole, and l32 represents the length of the first multi-blade support shaft (3-2); The fourth tool (4) is a second guide drill, comprising a fourth tool head (4-1), a tool rod (4-2) and a second multi-blade support shaft (4-21) coaxially connected from front to back, the fourth tool head (4-1), the tool rod (4-2) and the second multi-blade support shaft (4-21) are of equal diameter, satisfying l41>L3 and (L1+L3+L4+1.5D)-(l41+l42)≤(25%~30%)*L1; wherein l41 represents the length of the fourth tool head (4-1) and the tool rod (4-2) after being connected, and l42 represents the length of the second multi-blade support shaft (4-21); The fifth tool (5) comprises a fifth tool head (5-1), and the fifth tool head (5-1) is provided with a chip removal groove (5-10) from the front end thereof to the rear, and the length of the chip removal groove (5-10) is l51>L1+L3+L2; The specific steps of the processing technology are as follows: S1, using the first tool (1) to drill the guide hole of the front hole and chamfer and deburr the hole mouth, with a drilling depth of (1.5-2)*D; S2, using the second tool (2) to drill through the front hole to a depth of L1+(4-6) mm; S3, using the third tool (3) to countersink the inclined surface of the rear hole into a flat surface, with a processing depth of L1+L3+L4; S4, using the fourth tool (4) to drill the guide hole of the rear section hole to a processing depth of L1+L3+L4+1.5D; S5, using the fifth tool (5) to drill the rear hole to the depth required by the drawing, with the processing depth being L1+L3+L2.

2. The small-diameter intermittent deep hole machining tool set according to claim 1, characterized in that: The diameter d1 of the first cutting head (1-1) is The drill point angle α1 of the first cutting head (1-1) is 140°, and the drill depth l11 is 1.5D to 2D; Where D is the diameter of the hole to be processed.

3. The small-diameter intermittent deep hole machining tool set according to claim 1, characterized in that: The edge band of the second cutting head (2-1) comprises a double edge band (2-12) and a single edge band (2-11) coaxially connected from front to back, and the length l22 of the double edge band (2-12) is 6D to 7D.

4. The small-diameter intermittent deep hole machining tool set according to claim 3, characterized in that: The drill diameter d2 of the second tool (2) is The drill point angle α2 of the second tool (2) is 136°.

5. The small-diameter intermittent deep hole machining tool set according to claim 1, characterized in that: The third cutter head (3-1) is a two-tooth flat-bottom cutter head, the cutting edge length l33 of the third cutter head (3-1) is ≥ 2.5*L4, and the diameter d3 of the third cutter head (3-1) is d2-d3=0.005-0.025; The first multi-blade support shaft (3-2) has a rake angle α3=90°, a blade width β3=1.5, and a helix angle α31=20-25°.

6. The small-diameter intermittent deep hole machining tool set according to claim 5, characterized in that: The diameter of the blade body (3-10) of the third blade head (3-1) is shrunk on one side by 0.05 to 0.1 mm.

7. The small-diameter intermittent deep hole machining tool set according to claim 6, characterized in that: The first multi-blade support shaft (3-2) is a 6-blade support shaft.

8. The small-diameter intermittent deep hole machining tool set according to claim 1, characterized in that: The drill point angle α4 of the fourth cutter head (4-1) is 140°, the blade length l43 of the fourth cutter head (4-1) is 4D, the drilling depth is 1.5D to 2D, and the diameter d4 of the fourth cutter head (4-1) is 9. The small-diameter intermittent deep hole machining tool set according to claim 8, characterized in that: The diameter of the knife rod (4-2) is shrunk on one side by 0.05 to 0.1 mm.

10. The small-diameter intermittent deep hole machining tool set according to claim 1, characterized in that: The diameter d5 of the fifth cutting head (5-1) is The drill point angle α5 of the fifth cutting head (5-1) is 120°.

Images